Using generator functions in JavaScript for error handling

test-apis-by-generator-function.js

// Use case (?):
// Suppose you have an array of API keys from a service. We all know why you'd have multiple API keys of a single service.
// For some reason, you know that all of them are not gonna work at all times. This is the exact scenario replicated here. 

// Dummy array with, let's say, dummy API keys
const api_key_array = [
    "vikiohcucbigpinekjodumehdarhagbevrosolhivuvasodumsumvivahpiupaba",
    "leluralcotaimgamenfukhajuzkusamubiezilezigiczaduspiwovefniuzaleh",
    "wuvoneuvtucesilluleftovarkohlucukjarineetizokujunetejzaanviromdo",
    "foccuseucopozecepiogaejegafpellozumoderajewtotlomkigmecaluhindig",
    "gerionenifilkejepapdelpaefegogeronedtewcevsewafjubewojkaraujrari",
    "gonovevwojutomuvireelipoedujobhedaluemhukkajipmiegkefamuhobjuwee",
    "idukubteckergobedinihefnancufisjanalefuaradimebacvufnidujfanazuz",
    "vitiicvalacpoorgesozodzufawugalenattekujicoadmokacgevnadirbughea",
];

// The generator function
function* generateKeys(limit) {
    let num = -1;

    while (true) {
        if (num === limit) num = -1;
        num++;
        yield arr[num];
    }
}

// Declaring the iterator that returns the array values
const limit = api_key_array.length
let generator = generateKeys(limit);

// This is the real function that uses your API service. 
// Mind that this may be an infinite function if there are always errors.
// Hint: You've exhausted all of your API Keys' limits. Then this function runs for the whole day =)
function testGenerate(greeting1, greeting2) {
    try {
        let currentVal = generator.next().value;

        // Simulate an error
        let randomNum = Math.random();
        if (randomNum < 0.9) throw new Error("Uh Oh. Stinky.");

        // If no error occurs, use this currentVal returned by the generator function
        // along with arguments passed.
        console.log(`${greeting1}, ${currentVal}. ${greeting2}`);
        return;
    } catch (error) {
        // If an error occurs, call this function again with all the arguments
        console.log(error.message);
        testGenerate(...arguments);
    }
}

// First call to the function that uses the API key
testGenerate("Hello", "How are you?");

// More info on generator functions and using them:
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/function*
// https://javascript.info/generators